An integrated circuit (IC) module, of smart-type, that can be either a secure microcontroller or equivalent intelligence with internal memory or a memory chip alone, is normally packaged or embedded in a carrier (e.g. card). The resulting smart card device can be capable of connecting to a reader by direct physical contact, i.e. using contact-type interface defined by ISO (International Organization for Standardization) 7816, or by a remote contactless radio frequency interface, i.e. using contactless-type defined by ISO 14443, or both, i.e. using dual interface. With the embedded microcontroller, smart card devices are capable of storing large amounts of data, performing on-card functions (e.g. encryption, mutual authentication) and interacting intelligently with a smart card reader for various applications (e.g. banking, payment, telecommunications). The smart card devices may be packaged into various form factors (e.g. plastic cards, key fobs, watches, subscriber identification modules used in GSM mobile phones, USB-based tokens, the Secure Digital (SD), mini/micro SD, MMC, VQFN8, SSOP20, TSSOP20, MemorySticks cards, etc).
Generally, a method for fabricating a dual interface smart card device includes:
1(a) assembling IC chips with wire bonding connections and encapsulation onto a flexible substrate with metallic contact pads, wherein at least one IC chip and two antenna contact pads are mounted on the underside of a metallic contact pad to produce an IC module (FIG. 1A shows multiple IC modules 110, having contact pad layouts according to ISO 7816, being assembled on a flexible substrate);
1 (b) laminating a few substrate layers, which comprise an antenna coil inlay 130 interposed between two substrates 120, 140 of equal thickness, to produce a carrier core;
1 (c) milling the laminated carrier core to provide a plurality of first cavities wherein each first cavity is to receive an IC module;
1 (d) at each first cavity, further milling the laminating carrier a plurality of second cavities, which are smaller than the first cavity, to expose parts of the antenna wire coil;
1 (e) joining the exposed parts of the antenna wire coil to the two antenna contact pads provided on the underside of the contact pad;
1 (f) disposing an IC module into each first cavity such that a hot-melt tape on the underside of the IC module is applied to the laminated carrier core;
1 (g) applying heat and pressure to the IC module to embed the IC module in the laminated carrier core.
In step 1(e) above, the antenna coil may be joined to the antenna contacts on the underside of the IC module by using traditional wire soldering, flexible bumps or insertion of conductive materials to solder onto the antenna contacts to form an electrical connection from the IC module to the antenna coil to allow performance of contact-type and contactless-type transactions.
Generally, a method for fabricating a single interface, i.e. contact-type, smart card device includes:
2(a) assembling IC chips with wire bonding connections and encapsulation onto a flexible substrate with metallic contact pads, wherein at least one IC chip and two antenna contact pads are mounted on the underside of a metallic contact pad to produce an IC module (FIG. 1A shows multiple IC modules, having contact pad layouts according to ISO 7816, being assembled on a flexible substrate);
2(b) laminating a few substrate layers, which comprise two substrates of equal thickness, to produce a laminated carrier core;
2(c) milling the laminated carrier core to provide a plurality of first cavities wherein each first cavity is to receive an IC module;
2(d) disposing an IC module into each first cavity such that a hot-melt tape on the underside of the IC module is applied to the laminated carrier core;
2(e) applying heat and pressure to the IC module to embed the IC module in the laminated carrier core.
FIG. 1B shows a cross-sectional view of a smart card device 100 having a wire-bonded encapsulated IC module 110 embedded in a laminated arrangement. In the IC module 110, the IC chip 150 is provided with encapsulation 152 and located directly underside of the contact pad 160.